Dichlorodiphenyltrichloroethane specifically depletes dopaminergic neurons in primary cell culture

Toxicity of dichlorodiphenyltrichloroethane (DDT) to dopaminergic neurons in primary cell culture was investigated in the present study. Developing neurons from the substantia nigra of neonatal rats were cultured. After treatments with different concentrations of DDT (5-12.5 μM), specific cell death of tyrosine-hydroxylase-immunoreactive dopaminergic neurons was observed in the culture by flow cytometric analysis. More than 60% of dopaminergic neurons were depleted after treatments with 10 and 12.5 μM of DDT. In addition, significant reductions of intensity levels of tyrosine hydroxylase immunofluorescence were observed in dopaminergic neurons after DDT treatments even at low concentrations of DDT. The present findings indicate that dopaminergic neurons are more susceptible to DDT toxicity than other types of neurons in the primary cell culture. Moreover, it is shown that the synthesis of dopamine in dopaminergic neurons is also depressed. Previous studies have demonstrated that perinatal exposure of DDT causes neurons to be more susceptible to neurotoxic damages in later adult life. The present findings thus provide evidence that dopaminergic neurons that are undergoing growth and development are targets of DDT neurotoxic effects. Exposure to DDT from contaminated environments is therefore a potential risk of onset of Parkinson's disease.